In 1965, NEC completed the NEAC-32 high-capacity magnetic disk memory unit for the FONTAC computer of the Japan Electronic Computer Technology Research Consortium.
This unit reduced access time by providing 16 movable heads, held at a fixed spacing, for each disk side. The magnetic heads used a flying system and had a float distance of 7μm. Since the system had multiple disks and magnetic heads, and used the flying system, it was difficult to synchronize using a timing track, and an FM modulation system was adopted to enable self-synchronization using information signals.
| Total memory capacity(bit) | 270,336,000 | |
|---|---|---|
| Access time(msec) | 30-80 | |
| Latency time(msec) | Average 17 | |
| Disk dimensions(mm) | 650ø×3 | |
| Number of disks(for data) | 25 | |
| Number of recording sides(for data) | 48 | |
| Number of tracks(per side) | Inner zone 128+Outer zone 128 | |
| Track pitch(mm) | 0.6 | |
| Number of magnetic heads(per side) | Inner zone 8+Outer zone 8 | |
| Recording system | FM | |
| Recording density(bit/mm) | Max. 17 | |
| Rotation speed(rpm AC60Hz) | 1,800 | |
| Data transfer speed | Inner zone | 510kbit/s |
| Outer zone | 770kbit/s | |
| External dimensions(cm) | 178(W)×100(D)×180(H) | |
| Weight (kg) | Approx. 1000 | |
| Power requirements | 3KVA | |
